1. Field
The present invention relates generally to remote sensing and more particularly to passively communicating remote conditions by modulated reflectivity of an input electromagnetic signal.
2. Background
In resource recovery, it may be useful to monitor acoustic energy at locations remote from an observer. In particular, it may be useful to provide for monitoring conditions at or near to the bottom of a borehole that has been drilled either for exploratory or production purposes. Because such boreholes may extend several miles, it is not always practical to provide wired communications systems for such monitoring.